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ECE :: Communication Systems

  1. In VCR the luminance signal is recorded by

  2. A.
    frequency modulation
    B.
    phase modulation
    C.
    amplitude modulation
    D.
    direct recording

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  3. Assertion (A): In digital communication data is coded prior to being transferred.

    Reason (R): A number of codes for digital data processing are available.

  4. A.
    Both A and R are correct and R is correct explanation of A
    B.
    Both A and R are correct but R is not correct explanation of A
    C.
    A is correct but R is wrong
    D.
    A is wrong but R is correct

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  5. In FM modulation pre-emphasis is done for

  6. A.
    high frequency components
    B.
    low frequency components
    C.
    middle frequency components
    D.
    both (a) and (b)

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  7. c(t) and m(t) are used to generate an AM signal. The modulation index of the generated AM signal is 0.5 then the quantity
    is

  8. A.
    1/2
    B.
    1/4
    C.
    1/3
    D.
    1/8

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  9. High intermediate frequency in a superheterodyne receiver

  10. A.
    higher than
    B.
    lower than
    C.
    equal to
    D.
    not comparable to

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  11. The number of repeaters in a coaxial cable link depends on

  12. A.
    system bandwidth
    B.
    separation of equalizers
    C.
    the number of coaxial cables in the tube
    D.
    none of the above

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  13. The overall noise temperature Te, absolute temperature T and noise figure F are related as

  14. A.
    Te = T(F - 1)
    B.
    Te = F(T - 1)
    C.
    T = Te(F - 1)
    D.
    Te = (T)(F)

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  15. In binary data transmission DPSK is preferred to PSK because

  16. A.
    a coherent carrier is not required to the generated at the receiver
    B.
    for a given energy per bit, the probability for zero is less
    C.
    the 180° phase shifts of the carrier
    D.
    more protection is provided against impulse noise

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  17. A basic group B

  18. A.
    consists of five super groups
    B.
    has a frequency range of 60 to 108 kHz
    C.
    consists of erect channels only
    D.
    is formed at group translating equipment

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  19. By the use of which of the following the PPM can be converted to PWM?

  20. A.
    A stable multivibrator
    B.
    Integrator
    C.
    Monostable multivibrator
    D.
    Bistable Multivibrator

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